Targeting Fat: Mechanisms of Protein Localization to Lipid Droplets

Trends Cell Biol. 2016 Jul;26(7):535-546. doi: 10.1016/j.tcb.2016.02.007. Epub 2016 Mar 16.

Abstract

How proteins specifically localize to the phospholipid monolayer surface of lipid droplets (LDs) is being unraveled. We review here the major known pathways of protein targeting to LDs and suggest a classification framework based on the localization origin for the protein. Class I proteins often have a membrane-embedded, hydrophobic 'hairpin' motif, and access LDs from the endoplasmic reticulum (ER) either during LD formation or after formation via ER-LD membrane bridges. Class II proteins access the LD surface from the cytosol and bind through amphipathic helices or other hydrophobic domains. Other proteins require lipid modifications or protein-protein interactions to bind to LDs. We summarize knowledge for targeting and removal of the different classes, and highlight areas needing investigation.

Keywords: amphipathic α-helix; hydrophobic hairpin; lipolysis; organelle protein composition; triglyceride storage.

Publication types

  • Review
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cytosol / metabolism
  • Humans
  • Lipid Droplets / metabolism*
  • Lipid Droplets / ultrastructure
  • Models, Biological
  • Organelles / metabolism
  • Organelles / ultrastructure
  • Protein Transport
  • Proteins / metabolism*

Substances

  • Proteins